6B: Measuring Sleep

How is sleep measured if it cannot be directly observed?

By inferring from physiological responses or an individual's behaviour.

What types of data are used to measure sleep?

Physiological changes (objective) and qualitative information (subjective).

Name three objective measures of sleep.

EEG (Electroencephalograph), EMG (Electromyograph), EOG (Electro-oculograph).

Name two subjective measures of sleep.

Sleep diary and video monitoring.

What is a strength of objective measures?

Provide reliable, unbiased quantitative data.

What is a weakness of objective measures?

Do not give qualitative insights into someone's state of consciousness; physiological changes may be influenced by other factors.

What is a strength of subjective measures?

Can describe personal experiences and include both qualitative and some quantitative data.

What is a weakness of subjective measures?

Subject to bias; reliability and accuracy are limited.

What does the EEG do?

Detects, amplifies, and records electrical activity of the brain.

How does an EEG relate to sleep?

It identifies different brain waves which correlate to stages of sleep and consciousness.

What do brain waves represent?

The electrical activity of neurons in the brain.

What is frequency in brain waves?

The number of waves per second.

What is amplitude in brain waves?

The intensity or height of the waves.

What kind of EEG reading is seen during REM sleep?

Highest frequency, lowest amplitude; Beta-like waves

What kind of EEG reading is seen during NREM stage 1?

High frequency, low amplitude; Alpha-like waves

What kind of EEG reading is seen during NREM stage 2?

Medium frequency, medium amplitude; Theta-like waves

What kind of EEG reading is seen during NREM stage 3?

Low frequency, high amplitude; Delta-like waves.

What is one strength of the EEG?

Useful in sleep studies and diagnosing neurological disorders.

What is one limitation of the EEG?

Cannot precisely locate areas of brain activity due to the skull.

What does the EMG do?

Detects, amplifies, and records the electrical activity of body muscles.

What does the EMG measure during sleep?

Muscle tension and movement to indicate sleep stages.

What does the EMG show during REM sleep?

Low activity due to muscle paralysis.

What does the EMG show during NREM sleep?

Medium activity, decreasing as sleep deepens.

What does the EOG do?

Detects, amplifies, and records the electrical activity of eye muscles.

What does the EOG show during REM sleep?

High activity due to rapid eye movement.

What does the EOG show during NREM sleep?

Low activity since eyes are still.

What is a sleep diary?

A self-reported record about sleep patterns and perceptions kept over multiple nights.

What kind of data does a sleep diary provide?

Qualitative and subjective data.

List five types of information recorded in a sleep diary.

Duration, quality, thoughts before sleep, behaviours before and after sleep, number of disruptions.

What is a strength of sleep diaries?

Provide rich, detailed qualitative data about personal sleep experiences.

What is a limitation of sleep diaries?

Subjective and less reliable than objective tools.

What is video monitoring?

Using video and audio to observe and record a person while sleeping.

What can video monitoring track?

Movements, sleep behaviours, sounds made during sleep, and sleep/wake periods.

Why is video monitoring useful?

Helps identify behaviours in people with sleep disorders.

How can video monitoring add value to other measures?

It can be combined with physiological tools to validate results.